Efficient transcoding device and method

Claim 3

The device of claim 1, wherein said inverse transformation A i -1 is constant.

Claim 4

The device of claim 2, where the inverse transformation A i -1 is linear.

Claim 5

The device of claim 3, wherein said quantized vector Y i has dimensionality L=1.

Claim 6

The device of claim 4, wherein said inverse transformation A i -1 is an identity matrix.

Claim 7

The device of claim 3, wherein said modifying circuitry includes: a predictor, operably coupled to the quantization error vector calculator, for generating a predicted quantization error vector s i , and a transformation unit, operably coupled to the predictor, for utilizing a forward transformation A i [ ] for generating the modified quantization error vector S i .

Claim 8

The device of claim 6, wherein said quantization error vector calculator includes: a second adder, operably coupled to receive Y i ' and E i ', for determining the quantization error D i '=Y i '-E i ', and an inverse transformation unit, operably coupled to receive D i ', for utilizing an inverse transformation A i -1 to generate the vector d i ' according to d i '=A i -1 [D i '].

Claim 9

The device of claim 6, wherein said quantization error vector calculator includes: a second adder, operably coupled to receive Y i and Y i ', for determining an error X i '=Y i '-Y i , an inverse transformation A i -1 unit, operably coupled to the second adder, for generating a vector x i according to x i =A i -1 [X i '], and a third adder, operably coupled to receive the vector x i from the inverse transformation unit and to receive a feedback signal s i =A i -1 [X i '] from the predictor, for adding x i and s i to obtain the vector di'.

Claim 10

The device of claim 6 wherein the quantized vector Y i is generated by a predictive digital video encoder.

Claim 11

The device of claim 6 wherein said quantized vector Y i represents quantized transform coefficients of a macro block (MB).

Claim 12

The device of claim 9, wherein said predictor uses motion-compensated prediction (MCP) and transformation A[ ] is a Discrete Cosine Transform (DCT) and transformation A -1 is an inverse Discrete Cosine Transform (IDCT).

Claim 13

The device of claim 11, wherein said video encoder is an H.261 encoder.

Claim 16

The method of claim 13, wherein said inverse transformation A i -1 is constant.

Claim 17

The device of claim 14, where the inverse transformation A i -1 is linear.

Claim 18

The method of claim 15 wherein said quantized vector Y i has dimensionality L=1.

Claim 19

The method of claim 16, wherein said inverse transformation A i -1 is an identity matrix.

Claim 20

The method of claim 15 wherein the step of generating the modified quantization error vector S i based on past values of the vector d i ' includes: generating a predicted quantization error vector s i , and utilizing s i to generate the modified quantization error vector S i such that S i =A i [s i ] where A i is a predetermined transformation.

Claim 21

The method of claim 18, further including: utilizing received vectors Y i ' and E i ', for determining a quantization error D i '=Y i '-E i ', and utilizing an inverse transformation A i -1 to generate the vector d i ' according to d i '=A i -1 [D i '].

Claim 22

The method of claim 18, further including: receiving and utilizing vectors Y i and Y i ' for determining an error X i '=Y i '-Y i , utilizing inverse transformation A i -1 for generating a vector x i according to x i =A i -1 [X i '], and adding x i and s i to obtain the vector d i '.

Claim 23

The method of claim 18 wherein the quantized vector Y i is generated by a predictive digital video encoder.

Claim 24

The method of claim 18 wherein said quantized vector Y i represents quantized transform coefficients of a macro block (MB), a fundamental coding element in H.261.

Claim 25

The method of claim 22, further including utilizing motion-compensated prediction (MCP), and wherein transformation A[ ] is a Discrete Cosine Transform (DCT) and transformation A -1 is an inverse Discrete Cosine Transform (IDCT).

Claim 26

The method of claim 21, wherein said video encoder is an H.261 encoder.

Claim 27

A transcoding device for converting a sequence of quantized vectors Y i generated by a predictive waveform encoder utilizing modified quantization error vectors S i , comprising: (A) an adder, operably coupled to receive at least a first quantized vector Y i and at least a first modified quantization error vector S i , for generating a difference vector E i '=Y i -S i between the quantized vector Y i and the modified quantization error vector S i ; (B) a generalized quantizer, operably coupled to the adder and having a quantization error vector calculator, for quantizing the difference vector E i ' to obtain a transcoded vector Y i ', receiving at least one of the vectors Y i and E i ', for generating an inverse-transformed error vector d i '=A i -1 [D i '], where D i ' is a quantization error vector and A i -1 is an inverse transformation; and (C) modifying circuitry, operably coupling the quantization error vector calculator to the adder, for generating the modified quantization error vector S i based on past values of the vector d i '.

Claim 28

A transcoding device for converting a sequence of quantized vectors Y i generated by a predictive waveform encoder utilizing modified quantization error vectors S i , comprising: (A) an adder, operably coupled to receive at least a first quantized vector Y i and at least a first modified quantization error vector S i , for generating a difference vector E i '=Y i -S i between the quantized vector Y i and the modified quantization error vector S i ; (B) a generalized quantizer, operably coupled to the adder and having a quantization error vector calculator, for quantizing the difference vector E i ' to obtain a transcoded vector Y i ', receiving at least one of the vectors Y i and E i ', for generating an inverse-transformed error vector d i '=A i -1 [D i '], where D i ' is a quantization error vector and A i -1 is an inverse transformation; and (C) modifying circuitry, operably coupling the quantization error vector calculator to the adder, for generating the modified quantization error vector S i based on past values of the vector d i '.

Claim 29

The device of claim 25, wherein said inverse transformation A i -1 is constant.

Claim 30

The device of claim 26, where the inverse transformation A i -1 is linear.

Claim 31

The device of claim 27, wherein said quantized vector Y i has dimensionality L=1.

Claim 32

The device of claim 28, wherein said inverse transformation A i -1 is an identity matrix.

Claim 33

The device of claim 27, wherein said modifying circuitry includes: a predictor, operably coupled to the generalized quantizer, for generating a predicted quantization error vector s i , and a transformation unit, operably coupled to the predictor, for utilizing a forward transformation A i [ ] for generating the modified quantization error vector S i .

Claim 34

The device of claim 30, wherein said generalized quantizer includes: a quantizer, operably coupled to the adder, for quantizing an input vector E i ' to provide Y i ', a second adder, operably coupled to receive E i ' and Y i ', for determining the quantization error D i '=Y i '-E i ', where Y i ' represents a quantized vector for an input E i ' and an inverse transformation unit, operably coupled to receive D i ', for utilizing an inverse transformation A i -1 to generate the vector d i ' according to d i '=A i -1 [D i '].

Claim 35

The device of claim 30, wherein said quantization error vector calculator includes: a second adder, operably coupled to receive Y i and Y i ', for determining an error X i '=Y i '-Y i , an inverse transformation A i -1 unit, operably coupled to the second adder, for generating a vector x i according to x i =A i -1 [X i '], and a third adder, operably coupled to receive the vector x i from the inverse transformation unit and to receive a feedback signal s i =A i -1 [X i '] from the predictor, for adding x i and s i to obtain the vector d i '.

Claim 36

The device of claim 30 wherein the quantized vector Y i is generated by a predictive digital video encoder.

Claim 37

The device of claim 30 wherein said quantized vector Y i represents quantized transform coefficients of a macro block (MB).

Claim 38

The device of claim 30, wherein said predictor uses motion-compensated prediction (MCP) and transformation A[ ] is a Discrete Cosine Transform (DCT) and transformation A -1 is an inverse Discrete Cosine Transform (IDCT).

Claim 39

The device of claim 33, wherein said video encoder is an H.261 encoder.